Tuesday, April 03, 2012

Cocktail of Popular Drugs May Cloud Brain

Many people are unaware that dozens of painkillers, antihistamines and psychiatric medications — from drugstore staples to popular antidepressants — can adversely affect brain function, mostly in the elderly. Regular use of multiple medications that have this effect has been linked to cognitive impairment and memory loss.

Called anticholinergics, the drugs block the action of the neurotransmitter acetylcholine, sometimes as a direct action, but often as a side effect. Acetylcholine is a chemical messenger with a range of functions in the body, memory production and cognitive function among them.

The difficulty for patients is that the effect of anticholinergic drugs is cumulative. Doctors are not always aware of all of the medications their patients take, and they do not always think to review the anticholinergic properties of the ones they prescribe. It’s a particular problem for older patients, who are more vulnerable to the effects of these drugs and who tend to take more medicines over all.

Now a spate of new research studies has focused on anticholinergic medicines.

After following more than 13,000 British men and women 65 or older for two years, researchers found that those taking more than one anticholinergic drug scored lower on tests of cognitive function than those who were not using any such drugs, and that the death rate for the heavy users during the course of the study was 68 percent higher.

That finding, reported last July in The Journal of the American Geriatrics Society, stunned the investigators.

“So far we can’t tell why they are dying, but it wasn’t because they were sicker or older,” said Dr. Malaz A. Boustani, director of the Wishard Healthy Aging Brain Center and a scientist at the Regenstrief Institute, both in Indianapolis, who was one of the paper’s authors. “We adjusted for age, gender, race, other medications they were taking, other diseases and social status. We adjusted for everything we could, and that signal did not go away.”

He added: “These are very, very common drugs. That’s the scary piece.”

Dr. Chris Fox, a senior lecturer at Norwich Medical School at the University of East Anglia in England and the paper’s lead author, said he and his colleagues suspected that anticholinergics take a toll on bodily organs and systems like the cardiovascular system, although there are no studies confirming this.

Anticholinergics have also been implicated in the delirium that intensive-care patients frequently develop in the hospital. “Clinicians don’t think of them nearly as often as they should as a potential cause of cognitive problems,” said Dr. Wesley Ely, a professor of medicine at Vanderbilt University who studies neuropsychological deficits that occur after intensive care hospitalization.

Of the 36 million Americans 65 and older, at least 20 percent take at least one anticholinergic medication. A study by Dr. Boustani of nearly 4,000 older adults in Indianapolis found that those who had been using three or more possibly anticholinergic drugs consistently for 90 days or longer were nearly three times as likely to receive a diagnosis of mild cognitive impairment as those who had not taken anticholinergics.

“If you were taking one of the drugs we know is definitely an anticholinergic for 60 days, you doubled the odds of developing mild cognitive impairment” compared with a patient taking no anticholinergic medicines, Dr. Boustani said.

No association was found between chronic use of anticholinergics and dementia, however, even though mild cognitive impairment often precedes dementia. Dr. Boustani said the reasons for this were not clear.

Ask your pharmacist or doctor whether a drug you are taking is an anticholinergic. The usual advice—read the written material that comes with the drug—does not hold in this case. The much-abridged list of anticholinergics below came from a medical journal, but a spot check of the written information that comes with these drugs failed (with one exception) to mention the word anticholinergic.

Lomotil, Lofene, Logen, and many other drugs that contain atropine for diarrhea;